The Influence of Host Aphids on the Performance of Aphelinus asychis.

Abstract

Simple SummaryBiological control is one of the most environmentally friendly and economically sound alternatives to chemical insecticides in many agricultural systems. How to improve the biological performance and mass-rearing methods of natural enemies has become the main factor restricting the application of biological control. Aphelinus asychis Walker is an important aphid parasitic wasp and has been successfully used to control several pest aphids in greenhouses and fields. In this study, we compared the biological performance and stress tolerance of A. asychis, which was reared on different aphids. The findings in this study will be useful for mass-rearing and releasing of A. asychis to control many pest aphids in greenhouses and fields.The aphid parasitoid Aphelinus asychis Walker is an important biological control agent against many aphid species. In this study, we examined whether the rearing host aphid species (the pea aphid, Acyrthosiphon pisum and the grain aphid, Sitobion avenae) affect the performance of A. asychis. We found that A. pisum-reared A. asychis showed a significantly larger body size (body length and hind tibia length) and shorter developmental time than S. avenae-reared A. asychis. There was no difference in the sex ratio between them. The longevity of A. pisum-reared A. asychis was also significantly longer than that of S. aveane-reared A. asychis. Furthermore, A. pisum-reared A. asychis presented stronger parasitic capacity and starvation resistance than S. aveane-reared A. asychi. In addition, host aphid alteration experiments showed that A. asychis only takes two generations to adapt to its new host. Taken together, these results revealed that A. pisum is a better alternative host aphid for mass-rearing and releasing of A. asychis. The body size plasticity of A. asychis is also discussed.